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PASSWD(5) FreeBSD File Formats Manual PASSWD(5)
NAMEpasswd, master.passwd -- format of the password file
DESCRIPTION
The passwd files are the local source of password information. They can
be used in conjunction with the Hesiod domains `passwd' and `uid', and
the NIS maps `passwd.byname', `passwd.byuid', `master.passwd.byname', and
`master.passwd.byuid', as controlled by nsswitch.conf(5).
For consistency, none of these files should ever be modified manually.
The master.passwd file is readable only by root, and consists of newline
separated records, one per user, containing ten colon (`:') separated
fields. These fields are as follows:
name User's login name.
password User's encrypted password.
uid User's id.
gid User's login group id.
class User's login class.
change Password change time.
expire Account expiration time.
gecos General information about the user.
home_dir User's home directory.
shell User's login shell.
The passwd file is generated from the master.passwd file by pwd_mkdb(8),
has the class, change, and expire fields removed, and the password field
replaced by a `*' character.
The name field is the login used to access the computer account, and the
uid field is the number associated with it. They should both be unique
across the system (and often across a group of systems) since they con-
trol file access.
While it is possible to have multiple entries with identical login names
and/or identical user id's, it is usually a mistake to do so. Routines
that manipulate these files will often return only one of the multiple
entries, and that one by random selection.
The login name must never begin with a hyphen (`-'); also, it is strongly
suggested that neither upper-case characters or dots (`.') be part of the
name, as this tends to confuse mailers. No field may contain a colon
(`:') as this has been used historically to separate the fields in the
user database.
In the master.passwd file, the password field is the encrypted form of
the password, see crypt(3). If the password field is empty, no password
will be required to gain access to the machine. This is almost invari-
ably a mistake, so authentication components such as PAM can forcibly
disallow remote access to passwordless accounts. Because this file con-
tains the encrypted user passwords, it should not be readable by anyone
without appropriate privileges.
A password of `*' indicates that password authentication is disabled for
that account (logins through other forms of authentication, e.g., using
ssh(1) keys, will still work). The field only contains encrypted pass-
words, and `*' can never be the result of encrypting a password.
An encrypted password prefixed by `*LOCKED*' means that the account is
temporarily locked out and no one can log into it using any authentica-
tion. For a convenient command-line interface to account locking, see
pw(8).
The group field is the group that the user will be placed in upon login.
Since this system supports multiple groups (see groups(1)) this field
currently has little special meaning.
The class field is a key for a user's login class. Login classes are
defined in login.conf(5), which is a termcap(5) style database of user
attributes, accounting, resource, and environment settings.
The change field is the number of seconds from the epoch, UTC, until the
password for the account must be changed. This field may be left empty
to turn off the password aging feature; a value of zero is equivalent to
leaving the field empty.
The expire field is the number of seconds from the epoch, UTC, until the
account expires. This field may be left empty to turn off the account
aging feature; a value of zero is equivalent to leaving the field empty.
The gecos field normally contains comma (`,') separated subfields as fol-
lows:
name user's full name
office user's office number
wphone user's work phone number
hphone user's home phone number
The full name may contain an ampersand (`&') which will be replaced by
the capitalized login name when the gecos field is displayed or used by
various programs such as finger(1), sendmail(8), etc.
The office and phone number subfields are used by the finger(1) program,
and possibly other applications.
The user's home directory, home_dir, is the full UNIX path name where the
user will be placed on login.
The shell field is the command interpreter the user prefers. If there is
nothing in the shell field, the Bourne shell (/bin/sh) is assumed. The
conventional way to disable logging into an account once and for all, as
it is done for system accounts, is to set its shell to /sbin/nologin (see
nologin(8)).
HESIOD SUPPORT
If `dns' is specified for the `passwd' database in nsswitch.conf(5), then
passwd lookups occur from the `passwd' Hesiod domain.
NIS SUPPORT
If `nis' is specified for the `passwd' database in nsswitch.conf(5), then
passwd lookups occur from the `passwd.byname', `passwd.byuid',
`master.passwd.byname', and `master.passwd.byuid' NIS maps.
COMPAT SUPPORT
If `compat' is specified for the `passwd' database, and either `dns' or
`nis' is specified for the `passwd_compat' database in nsswitch.conf(5),
then the passwd file also supports standard `+/-' exclusions and inclu-
sions, based on user names and netgroups.
Lines beginning with a `-' (minus sign) are entries marked as being
excluded from any following inclusions, which are marked with a `+' (plus
sign).
If the second character of the line is a `@' (at sign), the operation
involves the user fields of all entries in the netgroup specified by the
remaining characters of the name field. Otherwise, the remainder of the
name field is assumed to be a specific user name.
The `+' token may also be alone in the name field, which causes all users
from either the Hesiod domain passwd (with `passwd_compat: dns') or
`passwd.byname' and `passwd.byuid' NIS maps (with `passwd_compat: nis')
to be included.
If the entry contains non-empty uid or gid fields, the specified numbers
will override the information retrieved from the Hesiod domain or the NIS
maps. Likewise, if the gecos, dir or shell entries contain text, it will
override the information included via Hesiod or NIS. On some systems,
the passwd field may also be overridden.
FILES
/etc/passwd ASCII password file, with passwords removed
/etc/pwd.db db(3)-format password database, with passwords
removed
/etc/master.passwd ASCII password file, with passwords intact
/etc/spwd.db db(3)-format password database, with passwords intact
COMPATIBILITY
The password file format has changed since 4.3BSD. The following awk
script can be used to convert your old-style password file into a new
style password file. The additional fields class, change and expire are
added, but are turned off by default (setting these fields to zero is
equivalent to leaving them blank). Class is currently not implemented,
but change and expire are; to set them, use the current day in seconds
from the epoch + whatever number of seconds of offset you want.
BEGIN { FS = ":"}
{ print $1 ":" $2 ":" $3 ":" $4 "::0:0:" $5 ":" $6 ":" $7 }
SEE ALSOchpass(1), login(1), passwd(1), crypt(3), getpwent(3), login.conf(5),
netgroup(5), nsswitch.conf(5), adduser(8), nologin(8), pw(8),
pwd_mkdb(8), vipw(8), yp(8)ManagingNFSandNIS (O'Reilly & Associates)
HISTORY
A passwd file format appeared in Version 6 AT&T UNIX.
The NIS passwd file format first appeared in SunOS.
The Hesiod support first appeared in FreeBSD 4.1. It was imported from
the NetBSD Project, where it first appeared in NetBSD 1.4.
BUGS
User information should (and eventually will) be stored elsewhere.
Placing `compat' exclusions in the file after any inclusions will have
unexpected results.
FreeBSD 10.0 June 23, 2012 FreeBSD 10.0